There is known a vehicular collision warning device that warns a driver when a collision risk is present so as to prevent a collision at an intersection with a vehicle outside a viewing field of a driver. (Refer to Patent Document 1.) In this device, a traveling direction detecting unit obtains a traveling direction, a speed detecting unit detects a speed, and a current position detecting unit detects a current position. Further, a communications control unit, a receiving unit, and a transmitting unit exchanges traveling directions, traveling speeds, and current positions between the subject vehicle and its neighboring vehicles. Through exchanging them, a computing unit determines whether an intersection is located within the distance D in the advancing direction. When an intersection is determined to be located within a distance D, the computing unit then determines whether any one of the neighboring vehicles approaches the intersection. When any one of the neighboring vehicles is determined to be approaching the intersection, a driver is warned of existence of the vehicle approaching the intersection through a displaying unit or a buzzer.
Patent Document 1: JP-H4-290200 A
Further, there are other positions where the subject vehicle may collide with or contact another vehicle, in addition to the intersection. For instance, when a vehicle passes an oncoming vehicle in a narrow road or when a subject vehicle is parked, there is possibility of colliding with another vehicle. In particular, suppose a case that a following vehicle is present when a subject vehicle passes an oncoming vehicle. In this case, a driver feels impatient to thereby not properly judge, so the driver may cause the subject vehicle to contact the oncoming vehicle or structures along roads or to run off road sides.